In mineral ore processing plants associated with mining operations, online sampling and analysis stations typically provide continuous in-stream analysis of composite samples for metallurgical accounting, enabling plant operators to follow and respond to process trends in real time. Such sampling and analysis stations generally include an inlet, an outlet, a stirrer, and a dedicated immersion probe analyzer mounted into the final tank of a full-flow sampling station designed to present to the analyzer a representative sample of the main ore slurry stream. The integrated immersion probe analyzer provides simultaneous analysis of typically up to 20 elements and percent solids in the slurry. Elements from calcium (Ca) to uranium (U) in the periodic table are measured by the immersion probe analyzer that typically includes a multi-element probe (MEP) using X-ray fluorescence (XRF), a proven and robust technology for plant environments.
In an XRF measurement using the immersion probe analyzer, the MEP uses an X-ray source to excite fluorescent X-rays from elements in the mineral ore slurry. Each element in the ore slurry emits fluorescent X-rays of an energy and intensity that is characteristic of that element and its concentration. Fluorescent and scattered X-rays from the ore slurry impinge on the detector of the MEP to produce small electrical pulses that are shaped, amplified, and counted. The peak amplitude of the pulse is proportional to the energy of the incident X-ray. The scattered X-rays are used to provide measurements of the ore slurry density. The number of X-rays is proportional to the elemental concentration in the ore slurry.
The detector of the MEP is typically a silicon drift detector (SDD). A typical detector configuration includes an SDD chip having a hot side in thermal contact with a Peltier-cooled heat sink that provides heat exchange with the SDD chip. An alternative approach to cooling the heat sink includes flowing liquid nitrogen (LN2) through the heat sink. Liquid nitrogen cooling, however, requires cryogenic storage and refilling.
Another alternative approach to cooling and controlling the temperature of an electronic component mounted on a heat sink, described in U.S. Pat. No. 8,937,482 B1, hereby incorporated by reference in its entirety (however, where anything in the incorporated reference contradicts anything stated in the present application, the present application prevails), is to flow the cold air output of a vortex tube through the heat sink.
As shown in FIG. 1, a vortex tube 100 takes in a pressurized air supply through an inlet 110 and produces a cold air output 120 and a hot air output 130. Depending on inlet air pressure and fraction of cold air output that is controlled by adjusting the hot air flow rate using control valve 140, the cold air temperature can be as low as −40° C., and the hot air temperature can be as high as 110° C. The surface of the vortex tube also becomes nearly as hot as the hot air output during operation. Additionally, a vortex tube produces very loud noise, in excess of 100 dBA, during operation. The high surface and hot air output temperatures and noise pose significant safety concerns for nearby operators.
Therefore, there is a need for a thermal control apparatus that reduces or eliminates the problems described above.